Police have used ground-penetrating radar to search the grounds of a North Plympton factory for the remains of the missing Beaumont children.

THEY gently grasp his forearms, a gathering of protective hands for a man seized by grief.

He walks forward, through the cars parked haphazardly along the road, through the long grass where his daughters were led.

Nearby, the body of his youngest girl lay in the dust of a dry creek bed, raped, strangled and stabbed.

Her sister is close by. Her face had been pushed into the sand until she suffocated. She’d been raped too. Then, after killing each girl, the murderer had plunged his knife three times into each tiny chest.

Police had found their school bags first. Then five-year-old Susan. Then, about 50m along the creek bed, seven-year-old Judith.

Their father is here to see them but the detectives’ grips are firm. They don’t want him near their naked little bodies, their clothes folded neatly in piles beside each girl.

School uniforms, folded neatly. Their straw hats were nearby. Two pairs of tiny shoes, a sock doubled over and placed inside each one.

The killer’s apparent proclivity for neatness would one day prove an important piece of the puzzle for police investigating the murders of Judith and Susan Mackay.

But it would be 28 years before they’d get Arthur Stanley Brown.

Arthur Stanley Brown in the late 1960sSource: News Corp Australia

Brown after his arrest in 1998 for the murdersSource: News Corp Australia

BORN in Queensland in 1912, Brown worked as a meatpacker in Townsville before taking a job as a maintenance carpenter with the Queensland Department of Public Works.

His work took him to various public buildings. Some of them were schools. One of those schools was the Aitkenvale State School, where Judith and Susan attended.

Colleagues described him as a private man whose clothing was always immaculate. He came to work each day with knife-edge creases ironed into his pants.

In 1944 he married divorcee Hester Porter. One of Hester’s sisters would later claim the mother-of-three was afraid of her new husband.

The sister said Hester had caught Brown molesting a child and had thereafter tried to prevent him being alone with younger relatives.

But as time went on, Hester became frailer. Crippled with arthritis, she took to her bed.

Children spent a lot of time at the house, helping with the housework. Between 1974 and 1976 there were three young relatives he abused on an almost daily basis.

While Hester was in bed he molested children in the house, the shower, outside the laundry and in their beds.

He took them on “family outings’’ to ride horses and to isolated swimming holes. One of those was at Anthill Creek, where the Mackay sisters had been found a few years earlier.

A frightened Hester had once handed over a family heirloom to a relative. It was a piece of lacework her mother had given her.

She didn’t want her husband’s next “ladylove’’ getting it, she explained.

The relative asked who she meant.

“Charlotte of course,’’ Hester had replied, referring to her younger sister.

On May 15, 1978, Hester died after apparently hitting her head in a fall. Charlotte and her children moved in soon after. Brown was married to his wife’s younger sister by year’s end.

The allegations of sexual assault were kept quiet until the 1980s when one of the girls confided in a friend.

Word spread through the family and mothers began questioning their children. More victims emerged. But police weren’t told right away.

The women were given legal advice that it was best not to press charges. A trial would be too traumatic.

Brown and his wife Charlotte, the younger sister of Brown’s first wife HesterSource: News Corp Australia

IN 1998, one of Brown’s victims picked up the phone and dialled Crime Stoppers. She had been watching television when a program came on about the unsolved murders of the Mackay sisters 28 years earlier. She’d always suspected Brown. And it was time police knew why.

Homicide detectives who had been conducting a cold case review got to work.

They interviewed family members and tracked down witnesses.

In December, Brown, by then aged 86, was charged with two counts of murder.

The arrest made headlines around the country and the former carpenter’s photograph was splashed across newspapers and on television news bulletins.

Within days police were getting more calls.

Brown matched descriptions given of a man seen with Joanne Ratcliffe, 11, and Kirste Gordon at Adelaide Oval when they were abducted during a football match in 1973.

This also led police to look into whether Brown was in Adelaide when the Beaumont children — Jane, 9, Arnna, 7, and Grant, 4 — disappeared from Glenelg beach in 1966.

“We are taking it seriously and we are seeing if there is any connection,’’ SA Police Detective Superintendent Paul Schramm said at the time.

“We have analysts working very closely together to try and piece together the last 30 years.’’

Information was impossible to come by though. With many records washed away in Queensland’s 1974 floods, police were unable to trace Brown’s movements.

Arthur Stanley Brown was charged 28 years after the Mackay murdersSource: News Limited

One relative, however, told police of a conversation she’d had with Brown where he mentioned seeing the Adelaide Festival Theatre when it was almost finished.

That would have put him in the city in 1973 — when Joanne and Kirste were taken from Adelaide Oval.

Detectives in Queensland considered him for the 1972 murder of Marilyn Wallman — Queensland’s only long-term outstanding missing child.

Marilyn was 14 when she disappeared on her way to school in Eimeo. Her brothers found her bike lying on its side after following behind.

A car matching Brown’s grey/blue Vauxhall was seen in the area at the time.

In 1975, teenager Catherine Graham was murdered near Townsville. She’d called her mother from a phone booth the night before her badly beaten body was found lying off the Flinders Highway, just outside of Townsville.

“There is someone peering at me mum — and I don’t like the look of him,’’ she said.

She’d been selling books door-to-door that day. She’d been seen knocking on doors close to Brown’s house.

Catherine Graham made a chilling final phone call to her mum before she was killedSource: CourierMail

Marilyn Wallman’s bicycle and belongings lie near cane fields in 1972. She’s never been seen sinceSource: News Limited

IT was 1970 when the Mackay sisters disappeared on their way to school.

On August 26, William Mackay came home from work to a frantic wife and the news his daughters had not made it home that afternoon.

“I got photos of the girls and went to the police,’’ he’d say in court.

“By eight o’clock that evening, friends and police had gathered and we searched backyards in the district.’’

It would be two agonising days before their bodies were found. Their brutal deaths shocked the people of Townsville — and the rest of Australia.

One local police officer vowed to never return home until the killer was caught. His wife brought him food and clean clothing as he worked around the clock, sleeping at the station.

Two weeks into the investigation he was dead of a heart attack.

Brown was never identified as a suspect.

But when the case went to trial in 1999, circumstantial evidence was presented linking him to the murders.

A teacher from the girls’ school, Judith Drysdale, had seen a man drive by slowly, staring at them ``intently’’.

She picked his photograph from a photo board.

``I’ve remembered that face for 29 years,’’ she said.

Nervous Townsville parents began driving their children to school after the Mackay sisters were abducted and murderedSource: Supplied

Other witnesses had seen a man matching Brown’s description in a car similar to his with two uniform-clad girls inside.

Service station attendant Jean Thwaite remembered saw a girl she later identified as Susan Mackay in a car as she filled the tank for a man.

The girl had red eyes and looked to have been crying.

“Are we there yet?’’ the girl had asked the man.

Ms Thwaite had also heard the girl’s sister speak to the man.

“When are you going to take us to mummy?’’ she’d asked.

“You promised you were going to take us to mummy.’’

“Get up on the seat and go to sleep,’’ the man had snapped.

Another witness had seen a man in a grey/blue Holden — similarly shaped to a Vauxhall — leaning across his car to speak to two young schoolgirls at a bus stop.

In 1975, Brown had confessed to a workmate that he was responsible for the murders.

“Police still haven’t solved the Mackay sisters’ murders. I wonder if they ever will,’’ John Hill had said as the pair drove past the local police station one day.

“I know all about that,’’ Brown had replied. “I did it.’’

Mr Hill thought his friend sounded serious. But he didn’t call police. He hadn’t thought his friend capable of such a crime.

Police claimed Brown had lied about the case.

“Those Mackay sister have me stumped,’’ he’d told an officer upon his arrest.

“I’ve lived in Townsville for 30 years and I haven’t heard of the Mackay sisters.’’

Justice Keiran Cullinane painted another picture for jurors.

“It forms one of the most notable events in the city’s post war history,’’ he said.

“I expect nobody in Townsville at the time would not be aware of it.’’

On October 28, 1999, the jury that was to decide Brown’s fate told the judge they could not reach a decision.

There would have to be a retrial.

The funeral for the Mackay sisters in 1970. Arthur Stanley Brown was charged in 1998 but a verdict could not be reached — a new trial did not go ahead due to Brown's dementia.Source: News Limited

Two years later, the director of public prosecutions announced the case would not proceed. A psychiatrist had found Brown was suffering from degenerative Alzheimer’s disease and was unfit to stand trial.

Sexual assault charges involving family members were also dropped. Brown had been facing 25 counts of indecent dealing with a child under 12, rape, attempted rape and stupefying with intent to commit an indictable offence.

The jury in his murder trial had not been allowed to know the allegations from his family that he’d been molesting young girls.

Brown’s second wife Charlotte died in 2002. He died three months later in a nursing home in North Queensland. On paper, Arthur Stanley Brown was an innocent man.

“I can’t believe such an insignificant little arsehole had such a profound effect on so many people’s lives,’’ his stepson Robert told crime writer Andrew Rule.

Judith and Susan’s parents fought for justice until the day Brown died.

William, the man who had been held back from seeing the broken bodied of his murdered daughters, is at least glad of that.

“I’m glad they didn’t let me see the girls because I wanted to remember them the way they were when I kissed them goodbye before leaving for work,’’ he said in 1999.

The Mackay family at the funeral service for sisters Judith and Susan MackaySource: News Corp Australia

A NOTE ABOUT RELEVANT ADVERTISING: We collect information about the content (including ads) you use across this site and use it to make both advertising and content more relevant to you on our network and other sites.